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Water Hyacinth – a simple aquatic beauty with a complicated back-story

26 November, 2022 11:10:04
Water Hyacinth – a simple aquatic beauty with a complicated back-story

Water hyacinth (Eichhornia crassipes) is a major freshwater weed found in lakes, rivers, and other water bodies across the globe. With high rates of regeneration, survival, and growth, it is generally difficult to clear water bodies infested with the weed. Water hyacinth forms dense colonies that block sunlight and crowd out native species and is regarded as the most troublesome aquatic plant.

Water hyacinth is not an indigenous species but was introduced to India during the British colonial rule as an ornamental aquatic plant from South America. It was brought to India by George Morgan, a Scottish migrant and jute merchant of Narayanganj, an industrial district in Dhaka, around the turn of the 20th century. Morgan was impressed by the beauty of the flowers and leaves and brought it with him to India. Once the aquatic weed got introduced into the water bodies of Bengal, it grew very fast and competed with the native species eliminating many of them. It complicated the ecology of the region.

At the beginning of the 20th century, the remarkable spread of this Amazonian aquatic weed contributed to agrarian decline and distress, prevented river transport, fishing, damaged bridges, and clogged dams. River navigation was obstructed, cultivation of wetland crops including deep-water Aman paddy and jute, became difficult, and consequently the economy of Bengal showed marks of stagnation. 

In the district of Mymensingh, for example, cultivators gave up producing any crop over an area of 100 square miles because of the extensive damage caused by the water hyacinth every year. In Khulna beel (marshy low land) areas, paddy cultivation was rendered difficult, and low-lying paddy suffered damage from the encroachment of the aquatic plant. The people of Nasirnagar in Comilla district petitioned the government, alleging that crops had been destroyed over a very large tract of their land by flooding and the proliferation of water hyacinth on cultivable land.

In 1914, the Narayanganj Chamber of Commerce considered the menace of the weed as one of ‘sufficient importance’ to bring it to the government’s attention. It was acknowledged by both government and non-government agencies that the water hyacinth had been ‘choking up the natural arteries of trade, impeding agricultural operations and menacing the health of the people’ in most parts of East Bengal. Under the circumstances, relevant laws of the government, such as the Bengal Waterways Act, Bengal Municipal Act, Bengal Local Self-government Act and Bengal Village Self-government Act, were geared up to fight the scourge, but to little effect. British administrators called researchers to fight against the menace to save the economy. 

The remarkable spread of this Amazonian aquatic weed contributed to agrarian decline and distress and divided the government and the public on the question of whether the pest should be completely eradicated or be subject to scientific research for profitable utilization. The idea of complete eradication was gradually replaced by efforts towards utilization. In the end, however, neither complete eradication nor fruitful utilization was possible.

At about the same time, Kenneth McLean, deputy director of the Department of Agriculture of East Bengal and Secretary to Water Hyacinth Committee, undertook a study of the chemical content of water hyacinth at the 'Dhaka Agricultural Farm' and found that it contained high levels of potash, nitrogen and phosphoric acid. McLean advised the government that concentrated research on water hyacinth may prove to be commercially viable after processing and utilized as fertilizers, animal feed or chemical ingredients.

McLean’s suggestion was taken up by the government and 850 maunds (a varying unit of weight equivalent to about 37 kg) of water hyacinth were collected and 499 maunds was stacked and left to rot. The rest was sun dried and then burnt. The experiment showed the percentage of nitrogen in the decomposed hyacinth came down to 0.72 percent, while when dried, it stood at 2.24 percent. In addition, 70 percent of the potash and 60 percent of the nitrogen were lost when it was decomposed, so scientists concluded the processing of the plants after drying was profitable.

As soon as researchers discovered that these aquatic plants found in abundance in the waterbodies in Bengal were a rich source of potash, it created quite a stir. This was around World War I and there was a major crisis of potash in the world market. Taking this opportunity, 'Messrs Shaw and Wallace & Co' proposed to the Indian government that they wanted a steady supply of good quality water hyacinth ash and was willing to pay Rs 84/- to 112/- per ton. After receiving a few rounds of samples, the company did not get the expected quality potash and declined to buy if the samples sent contained potash below 15 percent.   

So, the Government encouraged farming of good quality water hyacinth to extract high level of potash. But the provincial government of Bengal was opposed to commercial cultivation of the weed because the decision would hinder the growth of the agrarian economy in Bengal. The livelihood of the people of Bengal would be affected and the river-based communication system would be greatly damaged. Therefore, the 'Water Hyacinth Committee' was formed with seven members of the provincial government of Bengal. One of its members was Sir Jagadish Chandra Bose. 

Between 1921-22, the committee held seven meetings to decide on whether the weed should be eradicated, in what way, and if it was to be cultivated, what was the way to control its growth and spread. Although, they could not come to a concrete decision. They were hesitant about the economic viability of making fertilizers and extracting the chemical components from the water hyacinth plants. So, they left the decision in the hands of the provincial government, to destroy it by using manpower.

Meanwhile, C. A. Bentley, the then-Sanitary Commissioner of Bengal, connected the prevalence of cholera and malaria with water hyacinth. S.N. Sur, Assistant Director of Public Health, Malaria Research Unit, Bengal, insisted although water hyacinth is not directly related to diseases like malaria and cholera, but is indirectly responsible for the growth and spread of these deadly diseases. The water hyacinth creates a favourable habitat for Anopheles mosquitoes, responsible for malaria. Also, waterbodies infested with the weed and contaminated by feces is an ideal breeding ground for Vibrio cholerae. 

The ambivalent position of the state regarding the destruction or scientific utilization of the water hyacinth was evident as was the predicament of government in its quest for legislation to contain the weed. The legislative attempts at eradication were fraught with complications and failed miserably. The hyacinth was caught up in these machinations in interesting ways, though it was never tamed by the state.

Finally, the government decided to eradicate the water hyacinth by organized voluntary labour. The Water-hyacinth Act (1936) was enacted prohibiting all householders from keeping or tolerating water hyacinth on their holdings and premises and cooperating with government sponsored clearing drives. District collectors of affected zones were directed to organize water hyacinth destruction programmes involving locals to work voluntarily in the project.

A conservative estimate revealed that in 1936 the hyacinth covered an area of over 4000 square miles.9 The weed was mostly prevalent in the active delta, which comprised an area of around 35,000 square miles – implying that the hyacinth covered about one-ninth of the total deltaic plain.  The publicly sponsored clearance drives received an enthusiastic response from the people. Election (1937) manifestos of all major political parties promised to eradicate the water hyacinth. The eradication drive was further intensified after elected representatives assumed power in 1937 under the leadership of AK Fazlul Huq.

There are some additional reasons for the success of the water-hyacinth eradication programme. Heaps of water hyacinth, when decayed, make wonderful fertilizer for cropping. Moreover, some crops and vegetables grew luxuriously on the dressed water hyacinth heaps. This attracted many landless peasants to accumulate and heap water hyacinth to make floating fields for agricultural production.

By 1947 the scourge of the water hyacinth came under control and in the next decade the rivers of East Bengal became more navigable again. Water hyacinth still exists in many parts of the country as well as Bangladesh, particularly in the haors and beels, but these do not pose any serious problem to navigation or cultivation anymore. The plant is now utilized in alternative ways and chiefly used as manure; the leaf is used as fodder in floodplains when fodder is scarce. Handicraft items are also made from dried water hyacinth plants and these are getting a good response everywhere. 

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